An excellent extraction selectivity towards Sc over other REEs in 4 mol/L HCl solution was achieved with the separation factor βSc/REEs over 8000 by 2-ethylhexyl phosphoric acid mono 2-ethylhexyl ester(HEHEHP)and the...An excellent extraction selectivity towards Sc over other REEs in 4 mol/L HCl solution was achieved with the separation factor βSc/REEs over 8000 by 2-ethylhexyl phosphoric acid mono 2-ethylhexyl ester(HEHEHP)and the extraction equilibrium can be obtained within 20 min.The extracted Sc can be stripped using 5 mol/L NaOH solution as eluent at 363 K with the stripping rate of 92.1%obtained.The extraction mechanism was clearly elucidated by slope analysis,saturation extraction,IR,and NMR analysis.It was revealed that the extraction of Sc in 4 mol/L HCl solution is still dominated by cation exchange process between P-O-H and Sc,and coordination process between P=O and Sc,with 6 molecules of extractant as dimer participating in the process.Finally,a flowsheet for the recovery of Sc from ion-adsorption rare earth elements(REEs)concentrate was proposed and proved in lab-scale experiment.展开更多
The kinetcs of extraction of cobalt with HEHEHP-kerosene solution from aqueous nitrate solution has been studied using the Lewis Cell.The effects of stirring rate and interfacial area were investigated.In the kinetic ...The kinetcs of extraction of cobalt with HEHEHP-kerosene solution from aqueous nitrate solution has been studied using the Lewis Cell.The effects of stirring rate and interfacial area were investigated.In the kinetic region,the influences of concentration of cobalt,hydrogen ion and HEHEHP were mainly studied.The effects of the sulphate,chloride,nitrate and acetate ions in aqueous phase on extraction rate were also discussed. The experimental results indicate that the extraction process may be governed by the mixed mechanism of diffusion and chemical reaction.In the kinetion,region，the extraction Process might be controlled by the following interfacial reactions The apparent rate constant was calculated to be about 3.63×10-13mol·cm-2·s-1.The sulphate,nitrate and chloride ions decrease the extraction rate in the order of SO42-＞NO-3＞CI-.On the other hand,the acetate ion could greatly increase the extraction rate.The extraction rate with 0.025mol·L-1 acetate ion in aqueous phase is about four times of that without acetate ion.展开更多
The mass-transfer kinetics of ytterbium between aqueous solutions and heptane solutions of CA- 12 and CA-12-HEHEHP have been studied by using a constant interfacial area cell with laminar flow. The results have been i...The mass-transfer kinetics of ytterbium between aqueous solutions and heptane solutions of CA- 12 and CA-12-HEHEHP have been studied by using a constant interfacial area cell with laminar flow. The results have been interpreted according to a series of reversible interfacial reactions. In this work, it has been discovered that HEHEHP can increase the rate of ytterbium extraction by CA-12.展开更多
基金Projects(11705032,11975082,U1967218)supported by the National Natural Science Foundation of ChinaProject(2017GXNSFBA198175)supported by the Natural Science Foundation of Guangxi Province,ChinaProject(AA17204100)supported by the Science and Technology Major Project of Guangxi Province,China。
文摘An excellent extraction selectivity towards Sc over other REEs in 4 mol/L HCl solution was achieved with the separation factor βSc/REEs over 8000 by 2-ethylhexyl phosphoric acid mono 2-ethylhexyl ester(HEHEHP)and the extraction equilibrium can be obtained within 20 min.The extracted Sc can be stripped using 5 mol/L NaOH solution as eluent at 363 K with the stripping rate of 92.1%obtained.The extraction mechanism was clearly elucidated by slope analysis,saturation extraction,IR,and NMR analysis.It was revealed that the extraction of Sc in 4 mol/L HCl solution is still dominated by cation exchange process between P-O-H and Sc,and coordination process between P=O and Sc,with 6 molecules of extractant as dimer participating in the process.Finally,a flowsheet for the recovery of Sc from ion-adsorption rare earth elements(REEs)concentrate was proposed and proved in lab-scale experiment.
文摘The kinetcs of extraction of cobalt with HEHEHP-kerosene solution from aqueous nitrate solution has been studied using the Lewis Cell.The effects of stirring rate and interfacial area were investigated.In the kinetic region,the influences of concentration of cobalt,hydrogen ion and HEHEHP were mainly studied.The effects of the sulphate,chloride,nitrate and acetate ions in aqueous phase on extraction rate were also discussed. The experimental results indicate that the extraction process may be governed by the mixed mechanism of diffusion and chemical reaction.In the kinetion,region，the extraction Process might be controlled by the following interfacial reactions The apparent rate constant was calculated to be about 3.63×10-13mol·cm-2·s-1.The sulphate,nitrate and chloride ions decrease the extraction rate in the order of SO42-＞NO-3＞CI-.On the other hand,the acetate ion could greatly increase the extraction rate.The extraction rate with 0.025mol·L-1 acetate ion in aqueous phase is about four times of that without acetate ion.
文摘The mass-transfer kinetics of ytterbium between aqueous solutions and heptane solutions of CA- 12 and CA-12-HEHEHP have been studied by using a constant interfacial area cell with laminar flow. The results have been interpreted according to a series of reversible interfacial reactions. In this work, it has been discovered that HEHEHP can increase the rate of ytterbium extraction by CA-12.
